The purpose of this exploratory study is to determine the feasibility, acceptability, and efficacy of an exercise persistence intervention for patients with chronic obstructive pulmonary disease (COPD) following pulmonary rehabilitation (PR). Exercise, a cornerstone of PR, is effective in improving dyspnea, functioning, and health related quality of life (HRQL) in patients with COPD. However, these improvements gradually dissipate following program completion. There are currently few successful interventions that support patients' persistence with community-based exercise after PR and that have closely monitored the potentially negative impact that COPD exacerbations have on exercise behaviors. Emerging technologies such as wirelessly enabled personal digital assistants (PDA) may provide an innovative means to support exercise persistence through real-time collaborative monitoring of exercise and signs and symptoms of COPD exacerbations and reinforcement to enhance exercise self-efficacy. Patient graduates of 2 PR programs who have COPD (n=20) will first undergo a 2-week run-in prior to being randomized to either the MOBILE (Mobilizing Support for Long-term Exercise) intervention or attention control for 6 months. All subjects will individually meet with the PR coordinator and PI at baseline to discuss their exercise program and the importance of monitoring their exercise and symptoms with the PDA. The MOBILE intervention to be delivered via a PDA is based on social cognitive theory and has 3 components: 1) Collaborative exercise and symptom monitoring with automated alerts; 2) Motivational exercise prompting; and 3) Nurse feedback. Feasibility, acceptability, and satisfaction will be assessed. The mediators of exercise maintenance (self- efficacy for exercise, perception of support, and COPD exacerbation) and the primary outcomes of exercise behavior, performance, and HRQL will be measured at baseline, 3, and 6 months. Effect sizes will be calculated and exploratory analyses using RMANOVA will be performed. The findings from this exploratory study will lay the necessary groundwork for a longitudinal randomized controlled trial to test the effects of MOBILE with a larger and more diverse sample of patients with COPD at various stages of exercise adoption and maintenance. [unreadable] [unreadable]